Michigan, the hardest-hit state in a multistate outbreak of cyclosporiasis, on Thursday reported 13,909 cases linked to the parasitic disease, up roughly 11% over last week, but state officials said the rise largely reflected a processing backlog and the worst may be over.
The CDC on Thursday added two more states, Maine and Massachusetts, to the multistate outbreak linked to icebreg lettuce.
The 17-state outbreak of the parasitic disease, linked to iceberg lettuce, causes explosive diarrhea. It has shaken U.S. consumers nationwide, causing many to forgo eating fresh produce or dining in restaurants.
Lettuce sales plummeted last month, although diners are returning to restaurants, one of a few signs of improvement.
"The data suggests that new cyclosporiasis case reports are slowing," Laina Stebbins, a Michigan Department of Health and Human Services spokesperson, told Reuters, adding that some of the newly reported cases represented delays at laboratories.
Corewell Health, a non-profit chain of 21 hospitals across Michigan, issued guidance on July 22 saying that due to the current outbreak, it would take eight to 21 days to deliver test results, up from the normal two-to-four-day wait time.
Michigan now believes most of the contaminated produce is no longer available for consumption, Stebbins said.
Dr. Michael Osterholm, an infectious disease expert at the University of Minnesota, said it is important to understand when symptoms first emerged in the new cases.
The disease is especially challenging to trace because it has a two-week incubation period and unlike many other foodborne pathogens, it cannot be traced using the most advanced genetic testing methods.
Michigan previously reported two deaths associated with the outbreak, both occurring in individuals with significant underlying health conditions.
Within Michigan, Wayne County had the highest number of cases at 1,794, followed by Oakland County with 1,344. People aged 30 to 39 accounted for the largest number of cases by age group, with 2,615 infections. The state health department said 314 of those infected were hospitalized.